It looks to me like the new Lead on the play recognized that the players were going the wrong way. Look at where he is when he makes the GT call. It looks like he was coming out to stop play anyway. He made it to the end line, then starts walking out toward the Trail official. When the drive starts, he stops and officiates the play three steps onto the court.
If he'd just blown the whistle when he realized "something" was wrong. . .
